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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Anti-fungal
Generic Name
Anti-fungal Shampoo
Active Ingredient
KetoconazoleCategory
Azole Antifungal [EPC]
Variants
2
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Anti-fungal, you must consult a qualified healthcare professional.
Detailed information about Anti-fungal
Ketoconazole is a potent imidazole antifungal agent used to treat various fungal infections and certain endocrine disorders. It works by inhibiting the synthesis of ergosterol, a vital component of fungal cell membranes, and is available in both systemic and topical formulations.
The dosage of Ketoconazole varies significantly based on the form of the medication and the condition being treated. For systemic fungal infections, the standard oral dose for adults is typically 200 mg to 400 mg taken once daily. In severe cases, some healthcare providers may increase the dose to 600 mg or 800 mg per day, though higher doses significantly increase the risk of adrenal suppression and liver toxicity. For off-label use in Cushing’s syndrome, doses are highly individualized and may range from 400 mg to 1200 mg per day, usually divided into two or three doses to maintain consistent cortisol suppression.
For topical applications, the 2% cream is usually applied to the affected and immediate surrounding area once or twice daily for 2 to 4 weeks. The 2% shampoo is typically used twice weekly for 2 to 4 weeks for dandruff or seborrheic dermatitis, then used once every 1 to 2 weeks for maintenance to prevent recurrence.
Systemic (oral) Ketoconazole is generally not recommended for pediatric use because its safety and efficacy have not been well-established in children. In rare instances where it is deemed necessary by a specialist, dosing is usually based on body weight (e.g., 3.3 to 6.6 mg/kg/day). Topical Ketoconazole is considered safer for children, but it should still be used under the guidance of a pediatrician, particularly in infants where systemic absorption through the skin is more likely.
No dosage adjustment is typically required for patients with renal (kidney) impairment, as the drug is primarily cleared through the hepatobiliary (liver and bile) system. Ketoconazole is not significantly removed by hemodialysis.
Ketoconazole is contraindicated in patients with acute or chronic liver disease. Because the drug is both metabolized by the liver and potentially toxic to the liver, its use in patients with pre-existing hepatic impairment is extremely dangerous and generally avoided.
Dosage selection for elderly patients should be cautious, usually starting at the low end of the dosing range. This accounts for the higher frequency of decreased hepatic function and the increased likelihood of concomitant drug therapies that may interact with Ketoconazole.
If you miss a dose of Ketoconazole, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and return to your regular dosing schedule. Do not double the dose to catch up, as this increases the risk of side effects.
Signs of an oral Ketoconazole overdose may include severe nausea, vomiting, dizziness, or signs of adrenal insufficiency (extreme tiredness, low blood pressure). In the event of a suspected overdose, contact your local poison control center or seek emergency medical attention immediately. Treatment is generally supportive, as there is no specific antidote for Ketoconazole toxicity.
> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose without medical guidance. Regular blood tests are mandatory for those taking the oral form.
When taken orally, the most common side effects involve the gastrointestinal system. These include:
For topical use, the most common side effects are localized to the application site:
Ketoconazole is a high-risk medication when taken systemically. Patients must be aware that the oral form is no longer considered a first-line treatment for any fungal infection due to its safety profile. It should never be used for minor fungal infections like nail fungus or skin infections that can be treated topically. Before starting Ketoconazole, ensure your doctor has a complete list of all other medications you are taking, as the risk of dangerous drug interactions is exceptionally high.
Hepatotoxicity: Oral Ketoconazole has been associated with severe liver toxicity, including fatalities. Liver injury can occur even in patients without pre-existing liver disease. Healthcare providers must perform liver function tests (LFTs) before starting treatment and weekly or bi-weekly during treatment.
QT Prolongation: Co-administration of Ketoconazole with certain drugs that are metabolized by the CYP3A4 enzyme can result in increased plasma concentrations of those drugs, leading to QT interval prolongation and potentially fatal ventricular arrhythmias such as Torsades de Pointes.
Ketoconazole is one of the most potent inhibitors of the CYP3A4 enzyme system. Combining it with drugs that rely on this enzyme for clearance can lead to life-threatening toxicity. The following are strictly contraindicated:
Ketoconazole must NEVER be used in the following circumstances:
Ketoconazole is classified as FDA Pregnancy Category C. Animal studies have shown that high doses of Ketoconazole are teratogenic (cause birth defects), including syndactyly (fused fingers/toes) and oligodactyly. There are no adequate and well-controlled studies in pregnant women. Ketoconazole should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Systemic use during the first trimester is generally avoided unless the mother's life is at risk from a fungal infection.
Ketoconazole is excreted into human breast milk. Because of the potential for serious adverse reactions in nursing infants—including liver toxicity and interference with the infant's hormone production—a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
The safety and effectiveness of systemic Ketoconazole in children under the age of 2 have not been established. For children over 2, it is rarely used and only when other options are exhausted. Topical formulations are generally considered safe for children, though they should be used sparingly to avoid systemic absorption through the skin, especially in neonates.
Ketoconazole is a potent inhibitor of fungal cytochrome P450 14-alpha-demethylase (CYP51A1). This enzyme is responsible for the demethylation of lanosterol, a critical step in the synthesis of ergosterol. By depleting ergosterol, Ketoconazole compromises the integrity of the fungal cell membrane. Additionally, the accumulation of methylated sterol precursors disrupts the arrangement of the phospholipid acyl chains, leading to cell death. In humans, Ketoconazole inhibits several steroidogenic enzymes, most notably CYP17A1 (17-alpha-hydroxylase/17,20-lyase), which is why it reduces the production of testosterone and cortisol.
The antifungal activity of Ketoconazole is primarily concentration-dependent. Its effect on human hormones is also dose-dependent; higher doses (e.g., >400 mg/day) are required to see significant suppression of cortisol. The onset of action for topical forms is usually within a few days, but for systemic fungal infections, it may take weeks of continuous therapy to see clinical improvement.
| Parameter | Value |
|---|---|
Common questions about Anti-fungal
Ketoconazole is primarily used to treat a variety of fungal infections, including skin conditions like dandruff, athlete's foot, and ringworm when used topically. In its oral tablet form, it is reserved for serious, life-threatening systemic fungal infections such as histoplasmosis or blastomycosis, but only when other safer treatments are not an option. Additionally, it is used off-label to treat Cushing's syndrome because it can lower high cortisol levels. Because of the risk of liver damage, its oral use is strictly regulated by healthcare providers. Always consult your doctor to see which form of Ketoconazole is appropriate for your specific condition.
The most common side effects of oral Ketoconazole include nausea, vomiting, and abdominal pain, which affect more than 10% of patients. Topical versions, such as creams and shampoos, commonly cause localized skin irritation, itching, or a burning sensation at the application site. Some patients using the shampoo may also notice changes in hair texture or increased dryness of the scalp. If you are taking the oral tablets, you might also experience headaches or dizziness. It is important to report any persistent or worsening side effects to your healthcare provider immediately.
No, you should strictly avoid drinking alcohol while taking oral Ketoconazole. Both alcohol and Ketoconazole are processed by the liver, and taking them together significantly increases the risk of severe liver damage or hepatotoxicity. Some patients also experience a 'disulfiram-like' reaction when mixing the two, which includes symptoms like flushing, headache, nausea, and a rapid heartbeat. Even small amounts of alcohol can trigger these dangerous effects. If you have a history of heavy alcohol use, be sure to inform your doctor before starting this medication.
Ketoconazole is generally not recommended during pregnancy unless the potential benefits clearly outweigh the risks to the fetus. It is classified as FDA Category C, meaning animal studies have shown it can cause birth defects, such as fused fingers or toes, when given at high doses. There is limited data on its safety in human pregnancy, particularly during the critical first trimester. Topical use is considered lower risk because very little of the drug reaches the bloodstream, but it should still be used with caution. Always discuss your pregnancy status or plans to become pregnant with your doctor before using any form of Ketoconazole.
The time it takes for Ketoconazole to work depends on the type of infection being treated. For topical skin infections like athlete's foot or dandruff, you may notice an improvement in itching and redness within a few days, though the full course of 2 to 4 weeks is usually necessary to clear the fungus. For systemic infections treated with oral tablets, it may take several weeks of consistent use before clinical symptoms significantly improve. Because fungal infections can be stubborn, it is vital to continue the medication for the entire duration prescribed by your doctor. Stopping too early can lead to a relapse of the infection.
If you are taking Ketoconazole for a fungal infection, you should not stop taking it until you have finished the entire prescribed course, even if you feel better. Stopping early allows the remaining fungi to grow back, potentially leading to a more resistant infection. If you are taking Ketoconazole off-label for Cushing's syndrome, stopping suddenly can be dangerous as it may cause your cortisol levels to spike rapidly. Always consult your healthcare provider before discontinuing the medication. They will guide you on how to stop safely or transition to a different therapy if side effects occur.
If you miss a dose of Ketoconazole, take it as soon as you remember. If it is almost time for your next scheduled dose, skip the missed dose and continue with your regular schedule. Never take two doses at once to make up for a missed one, as this can increase the risk of serious side effects like liver toxicity or heart rhythm issues. Consistency is key to successfully treating fungal infections. If you find yourself frequently forgetting doses, consider using a pill organizer or setting an alarm on your phone to stay on track.
Ketoconazole is not typically associated with weight gain. In fact, when used to treat Cushing's syndrome, it may actually lead to weight loss as it lowers the abnormally high cortisol levels that cause abdominal fat accumulation. However, some patients may experience nausea or a loss of appetite, which could lead to temporary weight loss. If you notice rapid or unusual weight changes while taking this medication, it is important to discuss them with your doctor. They can determine if the weight change is related to the medication or an underlying health issue.
Ketoconazole has a very high risk of interacting with other medications, and many combinations are considered dangerous. It is a potent inhibitor of the CYP3A4 enzyme, which means it can cause other drugs like certain statins, blood thinners, and sedatives to reach toxic levels in your body. It also requires an acidic stomach to be absorbed, so antacids and acid-blockers can make it less effective. You must provide your healthcare provider with a complete list of all prescription drugs, over-the-counter medicines, and herbal supplements you are taking. Never start a new medication while on Ketoconazole without medical clearance.
Yes, Ketoconazole is widely available as a generic medication in several forms, including oral tablets, topical creams, and shampoos. Generic versions are required by the FDA to have the same active ingredient, strength, and effectiveness as the brand-name versions (such as the now-discontinued Nizoral tablets). Choosing the generic version can often be a more cost-effective option for patients. However, the availability of the oral tablets is more limited than the topical forms due to the strict safety guidelines surrounding their use. Check with your local pharmacist regarding the availability and cost of the generic formulation.
Other drugs with the same active ingredient (Ketoconazole)
> Warning: Stop taking Ketoconazole and call your doctor immediately if you experience any of these.
Prolonged use of systemic Ketoconazole can lead to chronic endocrine disruption. In men, this may manifest as chronic low testosterone, leading to muscle loss, mood changes, and breast enlargement. In women, it can cause menstrual irregularities. There is also a risk of developing chronic liver enzyme elevations, necessitating frequent monitoring. Long-term topical use is generally safe but can lead to localized skin thinning or chronic dermatitis in sensitive individuals.
The FDA has issued several Black Box Warnings for oral Ketoconazole:
Report any unusual symptoms to your healthcare provider.
If you are taking oral Ketoconazole, the following monitoring is mandatory:
Ketoconazole may cause dizziness or somnolence (drowsiness) in some patients. You should observe how the medication affects you before driving a car or operating heavy machinery. If you feel lightheaded, avoid these activities until the feeling passes.
Alcohol should be strictly avoided while taking oral Ketoconazole. Both alcohol and Ketoconazole are processed by the liver, and combining them significantly increases the risk of hepatotoxicity. Furthermore, some patients experience a "disulfiram-like reaction" (flushing, nausea, palpitations) when consuming alcohol with Ketoconazole.
Do not stop taking Ketoconazole abruptly if you are taking it for Cushing’s syndrome, as this could cause a rapid rebound in cortisol levels. For fungal infections, always complete the full course prescribed by your doctor, even if symptoms improve, to prevent the infection from returning or developing resistance.
> Important: Discuss all your medical conditions with your healthcare provider before starting Ketoconazole.
Ketoconazole can interfere with certain laboratory tests:
For each major interaction, the mechanism is usually the inhibition of the CYP3A4 enzyme, which prevents the liver from breaking down the second drug. This leads to increased toxicity of the co-administered drug. Management usually involves avoiding the combination or significantly reducing the dose of the second medication.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking.
Conditions requiring a careful risk-benefit analysis include:
There is a known cross-sensitivity among the azole class of antifungals. While some patients who are allergic to fluconazole (a triazole) may tolerate Ketoconazole (an imidazole), the risk of a cross-reaction is significant. A thorough allergy history must be taken before initiating therapy. If a rash or breathing difficulty occurs, the drug must be stopped immediately.
> Important: Your healthcare provider will evaluate your complete medical history before prescribing Ketoconazole.
Clinical studies of Ketoconazole did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. However, elderly patients are generally at a higher risk for hepatic toxicity and are more likely to be taking multiple medications that could interact dangerously with Ketoconazole. Liver function should be monitored even more closely in this population.
Since less than 15% of a Ketoconazole dose is excreted by the kidneys, renal impairment does not significantly affect the drug's pharmacokinetics. No specific dose adjustments are recommended for patients with kidney disease or those on dialysis. However, these patients should still be monitored for general tolerability.
Ketoconazole is contraindicated in patients with pre-existing hepatic impairment. The drug is extensively metabolized by the liver, and impaired liver function can lead to dangerously high levels of the drug in the blood, which in turn causes further liver damage. This creates a dangerous feedback loop that can lead to rapid liver failure.
> Important: Special populations require individualized medical assessment.
| Bioavailability | Variable (Requires Acid) |
| Protein Binding | 84% - 99% |
| Half-life | 2 hours (Initial), 8 hours (Terminal) |
| Tmax | 1 - 2 hours |
| Metabolism | Hepatic (Extensive) |
| Excretion | Fecal (57%), Renal (13%) |
Ketoconazole is classified as an imidazole antifungal. It is structurally related to other imidazoles like clotrimazole and miconazole but differs from triazoles (like fluconazole and voriconazole) by the number of nitrogen atoms in the five-membered azole ring. Imidazoles generally have a broader effect on human CYP450 enzymes compared to the more selective triazoles.